1-methyl-1-phenyl ethylene oxide when treated with HBr produce

Options

A.
B.
C.
D.

Explanation

To solve the problem of what 1-methyl-1-phenyl ethylene oxide produces when treated with HBr, we can follow these steps:

### Step 1: Identify the Structure
1. **Draw the structure of 1-methyl-1-phenyl ethylene oxide.**
- Ethylene oxide is a cyclic ether (an epoxide) with the formula C2H4O.
- The compound has a methyl (–CH3) and a phenyl (–C6H5) group attached to the first carbon of the ethylene oxide.
- The structure can be represented as follows:
```
O
/ \
CH3 C6H5
```

### Step 2: Reaction with HBr
2. **Understand the reaction mechanism with HBr.**
- When 1-methyl-1-phenyl ethylene oxide reacts with HBr, the oxygen atom in the epoxide ring has a lone pair that can attack the hydrogen (H+) from HBr.
- This leads to the formation of a protonated epoxide, where the oxygen becomes positively charged (O+).

### Step 3: Formation of Carbocations
3. **Determine the possible carbocations formed.**
- The protonation of the oxygen leads to a transition state where the epoxide ring can open.
- There are two possible sites for the ring to open:
- If the bond between the oxygen and the carbon attached to the phenyl group breaks, it leads to a tertiary carbocation.
- If the bond between the oxygen and the carbon attached to the methyl group breaks, it leads to a primary carbocation.
- The tertiary carbocation is more stable due to hyperconjugation and resonance stabilization from the phenyl group.

### Step 4: Nucleophilic Attack
4. **Nucleophilic attack by bromide (Br-).**
- The bromide ion (Br-) present in the solution will attack the more stable carbocation (the one formed from the phenyl group).
- This results in the formation of the final product.

### Step 5: Final Product Structure
5. **Draw the final product.**
- The final product will have a bromine atom (Br) attached to the carbon that was part of the carbocation, and the hydroxyl group (OH) will be on the other carbon.
- The structure of the final product can be represented as:
```
OH
/ \
CH3 C6H5
\
Br
```

### Conclusion
The major product formed when 1-methyl-1-phenyl ethylene oxide is treated with HBr is a compound containing a bromine atom, a hydroxyl group, a methyl group, and a phenyl group.